Cannot connect using phone. Webbrowser and/or app

I am somehow unable to connect to Volumio from my phone.
Either using the webbrowser or the app.

My phone is on the same subnet as all my devices and computers, and connecting to it from my laptop or desktop is no problem at all.
It just times out on the phone.

Also, this is with both the DNS name as well as the IP address.
Not that it should matter, but tested either way.

What could cause this?

Do you see the volumio hotspot?
Can you connect to that and check the network config or finish network setup?

After installation I used a monitor/keyboard/mouse to do the initial configuration.
Volumio Hotspot is disabled.

As I have configured the network setup, what do you want me to finish?

Volumio is designed to run headless and be managed by a web browser or phone app.

I know that. That is why I disabled the HDMI, which is enabled by default afaik.

Then why this?
“I used a monitor/keyboard/mouse to do the initial configuration.”